There is a remarkable psychological theory that explains the paradox of why so often our pleasures turn into problematic addictions and, conversely, why our stressful experiences frequently lead to sustained good feelings and even happiness. This under-appreciated theory was developed in the 1970s by behavioral psychologist Richard Solomon of the University of Pennsylvania. He published his theory and findings in 1980 in the journal American Psychologist, as a seminal paper, “The Opponent-Process Theory of Acquired Motivation: The Costs of Pleasure and the Benefits of Pain”. Solomon’s theory has been verified experimentally with animals and humans, and reflects a sophisticated understanding of the physiology of the nervous system. It provides a framework that has been used to explain behaviors and emotional experiences in areas as diverse as addiction, thrill-seeking, love, job satisfaction, and cravings for food or exercise. I believe it can also explain the psychological benefits of cold showers that I have described in a separate post here, and why these benefits increase with time and repetition. I would urge followers of this blog to read Solomon’s paper, via the above hyperlink. It provides many important insights regarding how to effectively and reliably use challenge and stress to increase mental and emotional resilience, while maximizing your motivation and enjoyment in doing so. In this post, I will explore Solomon’s theory in some detail, and suggest some practical strategies for how to enhance pleasure and satisfaction in everyday activities, while avoiding the addictive side of pleasure.
Consider the following ten situations:
- Drug addicts, before becoming addicted, experience the euphoria of a drug with few negative consequences. Over time, however, they develop a tolerance for the drug, requiring increasing doses to get the same high. At the same time, their cravings and distressful feelings increase when going without the drug, leading to increased in withdrawal symptoms and a cycle of increasing drug use.
- Firefighters and emergency room doctors have stressful jobs, but many find themselves experiencing an irresistible rush and heart-throbbing exhilaration from these fast-paced occupations.
- New lovers, after a honeymoon period of initial infatuation, often experience a drop-off in affection, leading to dissatisfaction, fights, and sometimes breakups. When reconciling after the breakup, they experience renewed closeness for a period of time. Typically, the more intense the infatuation, the greater the strife and negativity during the falling out periods.
- Marathoners and other runners often experience a “runner’s high” which builds up during longer, more strenuous runs, and can extend for hours or even days after a run. Runner’s high has been associated with release of endorphins, a natural “opiate” produced by the body.
- Infants who are given a bottle and start sucking on it experience pleasure. But if the bottles are removed before the infants have finished feeding, they universally cry. And yet they would not have cried if the bottle had never been given.
- Depressed adolescents often resort to “cutting”, a form of self-mutilation that introduces some pleasure or even a high into their otherwise sad or pleasureless day. They often find the need to increase the cutting to maintain the pleasure.
- Scratching an itch generally relieves the itch and can be pleasurable, but often this ends up making the itch more intense and, after repeated itching, even painful.
- Horror movies, which initially are disturbing or even terrifying, can become addictive
- Politicians and executives in positions of power come to crave the power. When they are out of the limelight, they experience a letdown, boredom, or even depression. Upon retirement, this depression can lead to poor health or shortened longevity.
- People who donate blood frequently report a sense of well being and pleasure that cannot be explained in terms of the blood removal itself.
Can you see the pattern? In the odd-numbered examples above, pleasure turns to pain; in the even numbered examples, pain becomes pleasure. And in all cases, the effect intensifies with repetition. But why does this occur? One possible explanation for these types of situation is described in William Irvine in his book “A Guide to the Good Life”:
The psychologists Shane Frederick and George Loewenstein have studied this phenomenon and given it a name: hedonic adaptation. To illustrate the adaptation process, they point to studies of lottery winners. Winning a lottery ticket typically allows someone to live the life of his dreams. It turns out, though, that after an initial period of exhilaration, lottery winners end up about as happy as they previously were. They start taking their new Ferrari and mansion for granted, the way they previously took their rusted-out pickup and cramped apartment for granted. (Irvine, p. 66).
Hedonic adaptation is the experience of “getting used to” a good or pleasurable thing until one returns to a state of relative indifference or equilibrium, feeling about the same as one did beforehand. As I describe in more detail on the Stoicism page of this blog, Irvine goes on to point out how the Greek and Roman Stoics were able to combat hedonic adaptation by practicing techniques such as “negative visualization”, in which they regularly took time to vividly imagine loss of people, relationships and possessions they held dear, so they could better appreciate what they had.
Hedonic reversal and habituation. While hedonic adaptation of this sort certainly exists, the ten situations I listed above are quite different than than that of the lottery winner that Irvine describes. My ten situations do not involve a return to homeostasis or equilibrium. They involve a total switch, what I will call hedonic reversal. Pleasure becomes pain; pain turns to pleasure. This is the phenomenon that Richard Solomon tries to explain in his paper. Solomon quotes Plato, who may been the first to describe true hedonic reversal and puzzle over it:
How strange would appear to be this thing that men call pleasure! And how curiously it is related to what is thought to be its opposite, pain! The two will never be found together in a man, and yet if you seek the one and obtain it, you are almost bound always to get the other as well, just as though they were both attached to one and the same head….Wherever the one is found, the other follows up behind. So, in my case, since I had pain in my leg as a result of the fetters, pleasure seems to have come to follow it up.
In hedonic reversal, a stimulus that initially causes a pleasant or unpleasant response does not just dissipate or fade away, as Irvine describes, but rather the initial feeling leads to an opposite secondary emotion or sensation. Remarkably, the secondary reaction is often deeper or longer lasting than the initial reaction. And what is more, when the stimulus is repeated many times, the initial response becomes weaker and the secondary response becomes stronger and lasts longer. This is what happens quite clearly in the case of addiction. After repeated administration, the original dose no longer gives the same high, so it must be increased to achieve that effect. In addition, as time goes on, abstaining from the addictive dose becomes more difficult, while cravings, anxiety and depressive feelings increase. The mirror image of this addictive pattern is apparent in the case of endorphin-producing athletic activities like running, or thrill-seeking pasttimes like parachuting. Solomon reports on a study of the emotional reactions of military parachutists:
During the first free-fall, before the parachute opens, military parachutists may experience terror: They may yell, pupils dilated, eyes bulging, bodies curled forward and stiff, heart racing and breathing irregular. After they land safely, they may walk around with a stunned and stony-faced expression for a few minutes, and then they usually smile, chatter, and gesticulate, being very socially active and appearing to be elated….The after-reaction appears to last about 10 minutes…After many parachute jumps, the signs of affective habituation are clear, and the fearful reaction is usually undetectable. Instead, the parachutists look tense, eager or excited, and during the free-fall they experience a “thrill”. After a safe landing, there is evidence of a withdrawal syndrome. The activity level is very high, with leaping, shouting…and general euphoria. This period, often described as exhilaration, decreases slowly in time, but often lasts for 2-3 hours. Indeed, I was once told by a sport parachutist…that his “high” lasted 8 hours. A new, positive source of reinforcement is now available, one that could never have eventuated without repeated self-exposures to an initially frightening situation to which the subject then becomes accustomed. (Solomon, pp. 693-8)
Thus, both the addictive pattern and the thrill pattern share the features of hedonic habituation (reduced intensity of the primary response) and hedonic withdrawal (heightened intensity of the secondary, opposite response). In surveying and studying a wide range of such experiences, Solomon found a common pattern of hedonic contrast, which he represented as follows:
baseline state → State A → State B
State A is the initial emotional or “affective” response to a stimulus, which can be either pleasant or unpleasant. Typically, the first time a novel stimulus is applied, the primary or State A response is most pronounced at the outset and then tapers to steady level as long as the stimulus is maintained, as shown below in Figure 4. For example, exposure to the heat of a sauna or hot tub may cause an initially hot or burning sensation, which diminishes somewhat over time. Once the stimulus is removed, the sensation is replaced by a contrasting sensation or affective state, the after-reaction, or State B. State B is opposite in hedonic character to State A. If one is pleasant, the other is unpleasant, and vice versa. Initially, and after the first few stimulations, State B typically has a much lower intensity than State A, but often lasts longer in duration, before it eventually decays and returns to the baseline state.
What Solomon noticed is that after many repeated stimulations, the intensity of State A typically diminishes, both in peak intensity and steady state intensity. This is the hedonic habituation effect, also called “tolerance”, and it is seen with both pleasant and unpleasant affective reactions. The only way to increase the intensity of State A is to increase the magnitude of the stimulus. At the same time, with repeated exposures, the secondary affective State B often intensifies and lasts longer. This is the hedonic withdrawal effect. This combination of habituation and withdrawal effects is shown in Figure 5: For addictions, the pleasurability of the stimulus diminishes with time and the unpleasant withdrawal grows in both intensity and duration. For the thrill-seeking or excitatory pattern, the stressfulness or unpleasantness of the stimulus is reduced with repetition, while the “withdrawal” becomes more pleasant and lasts longer, before returning to baseline.
The opponent-process theory. So far, all we have presented is a qualitative description of some common patterns of sensory or emotional response, without any real explanation for why these patterns occur as they do. But Solomon’s real innovation is that he can explain these patterns by decomposing them into more elemental underlying biological processes. His central insight is that the nervous system is organized in such a way that any sensory or emotional response can be decomposed into two concurrent processes. The State A response diagrammed in Figures 4 and 5 above is in reality a composite of two complementary physiological processes:
- a primary process “a”, which is the direct observable response to the stimulus; and
- an opponent process “b”, which acts to inhibit or counteract the primary process. It occurs at the same time as the primary process, but is not always evident or easy to perceive.
To understand how these processes actually work in practice, let’s look more closely at Figure 7 below. The opponent process “b” actually begins shortly after the initiation of the primary process “a” and acts to dampen it during what we observe as State A. Because “b” is both smaller and opposite in effect to “a”, it acts to reduce the net impact of “a”. That explains why the intensity of the A process is greatest at the outset, but drops as the stimulus in continued. According to Solomon, for a novel stimulus the “b” process is smaller and more sluggish than the “a” process. It is slower to built to its steady state level (asymptote) and slower to decay after the stimulus stops. This is shown in Panel A of Figure 7:
So what happens to bring about habituation after many repetitions of the stimulus, when the stimulus is no longer novel? According to Solomon, the primary “a” process remains unchanged in response to the stimulus. What changes with repetition is the opponent process “b”. As depicted in Panel B of Figure 7, after many stimulations:
- it intensifies
- it starts earlier (reduced latency period)
- it decays more slowly
The net impact of these changes in the opponent process is to progressively dampen the magnitude of State A and increase the speed, magnitude and duration of State B. Thus, without any changes in the primary process, these changes in the opponent process can fully explain the increase in both tolerance and withdrawal, as shown in Figure 7.
Biological basis. Opponent processes are not just some clever hypothetical construct that Solomon came up with out of thin air. These kinds of inhibitory processes are common in biological systems. For example, many or perhaps most neurotransmitters, hormones, and biological receptors have corresponding opposites, which act to inhibit or moderate the primary response. These inhibitory processes serve a useful biological control functions by preventing over-reactions to environmental disturbances. They form the the biological basis of systems of homeostasis, systems that enable organisms to resist or adapt to disturbances to their steady functioning.
Solomon’s opponent-process theory also identifies several key factors that can strengthen or weaken the opponent “b” process. His paper summarizes some very clever animal research on distress behavior in ducklings, from which he deduced that the opponent process can be strengthened in three primary ways:
- increasing the intensity of the initial stimulus exposure
- increasing the duration of the stimulus
- shortening the interstimulus interval (the time between stimulus exposures)
Interestingly, merely repeating the stimulus, in and of itself, had no effect on strengthening of the opponent process if the stimulus was too weak or too short, or if the interstimulus interval was too long. In particular, he found that, depending on the inherent duration of the opponent process, the interstimulus interval had a major effect on whether or not the opponent process will increase in strength. According to Solomon
The critical decay duration is that disuse time just adequate to allow the weakening of the opponent process to its original, innate reaction level. If reinforcing stimuli are presented at interstimulus intervals greater than the decay duration, then the opponent process will fail to grow. (Solomon, p. 703)
Each opponent process has an inherent decay behavior, that is, a rate at which it fades away. This will depend on the specific physiological and biological underpinnings of that process. On a biochemical level, for example, this decay duration may depend on the half-life of the neurotransmitters, hormones, or receptor behavior involved. It will surely also involve higher order processes which relate to the nervous system and psychological conditioning of the individual. Figuring out the decay duration of various opponent processes should be a matter open to empirical determination. It can be approached both by psychological investigations on others (or on oneself), and also by looking into the underlying physiological and biochemical mechanisms.
The final element of Solomon’s theory is a phenomenon he calls “savings”. Although opponent processes can be weakened or faded away by avoiding the stimulus for an extended period of time, that does not mean they leave no memory traces. Studies show that these opponent processes are more quickly reactivated the next time they are re-stimulated. Reflexes and emotional reactions build up more quickly when reactivated than they did with the initial stimulation. According to Solomon,
Such a phenomenon is not unexpected. In alcohol addiction, for example, the abstainer is warned that one drink may be disastrous, and the reason is the savings principle. The reexercise of alcohol’s opponent-process system strengthens the withdrawal syndrome very rapidly and sets up the special conditions for resumption of the addictive cycle. Cigarette smokers report the same phenomenon: Readdiction to nicotine takes place much more rapidly than does the initial addiction. (Solomon, p. 703)
This savings effect also applies to positive opponent effects, such as the exhilaration experienced by skydivers or runners when resuming their thrilling or strenuous activities after a hiatus. Understanding this effect is important in designing strategies for avoiding or minimizing the negative effects of relapse, as will be discussed below.
Put into simplest terms, the opponent-process theory explains the psychology of addiction and thrill-seeking in terms of the strengthening of inhibitory processes. These inhibitory processes get stronger when stimulation of a primary emotional response is sufficiently intense, sustained and frequent. They become evident only when the stimulus and the primary processes are absent, and typically last for some time afterwards. On subsequent re-exposure the stimulus, opponent processes often reactivated more quickly.
Is this a biologically realistic explanation? Perhaps Solomon has not generated a broad enough set of hard physiological data to conclusively prove his hypothesis. However, there is still a strong case in favor of it. First, his hypothesis provides a model which offers a coherent and consistent explanation for a wide range of sensory and emotional behaviors for which there are few other good explanations. Second, there one application of the Opponent-Process theory–to an area unrelated to emotions–which has already been empirically verified: the explanation of color perception. It is worth spending a paragraph on this because it provides some insights into the biological reality of this theory.
The opponent-process theory of color vision. Until the late nineteenth century, the primary theory of color vision was the trichromatic theory, which held that color perception was the result of the stimulation of three different types of cone receptors in the retina of the eye. In 1892, Ewald Hering first proposed the opponent-process theory of color vision. He observed that any color can be uniquely analyzed in terms of the colors red, yellow, green, and blue, and noted that these four primary colors exist as the complementary pairs red-green and yellow-blue. Hering’s theory accounts for how the brain receives signals from different kinds of cone cells and processes and combines these signals in real time. The opponent-process theory of color vision received further support in 1957 in studies by Hurvich and Jameson, and in 2006 by Liapidevskii. Some of the most compelling evidence for the theory is the phenomenon of complementary color after-images, which cannot be explained by the tricolor theory. You can demonstrate this for yourself by staring at the red dot in the middle of the image below for 30 seconds without letting your eyes drift from the center; then look at a blank white sheet and you will see the image with a more familiar set of colors. (It may take a while for the image to develop).
Looking at the colors under bright light and for longer periods enhances the opponent (inhibitory) processes in the receptors, which intensifies the after-images, just as one would predict based on the principles Solomon found for sensation and emotion.
Consider the similarity between this contrasting after-image response to visual stimuli and the emotional or affective responses that that Solomon found in his animal studies. The sensory after-images may be less intense and of shorter duration, but the principle is the same, and both phenomena illustrate how opponent processes can arise within our nervous systems. Beyond the processing of simple nerve signals, such as those involved in visual sensory perception, the opponent process theory can account for psychological processes of increasing complexity and at multiple levels, based on the well established fact that the brain is able to integrate sensory information by adding and subtracting different excitatory and inhibitory inputs from different receptors and neurotransmitters.
Practical applications. Besides explaining common sensory and emotional reactions, I believe the opponent-process provides some very practical guidance for how we can use pleasant and unpleasant experiences to our advantage. This guidance can be boiled down to seven basic insights:
- Be aware of hidden processes! The most important insight is to be aware that any primary sensory or emotional stimulus, whether pleasurable or unpleasant, will give rise to opponent processes of an contrasting nature. Even though you most likely cannot directly perceive them, these opponent processes are happening–and even growing in strength–at the very same time as the primary emotions and sensations that you do perceive. When the primary emotions and sensations stop or pause, these contrasting processes emerge into consciousness! For example if you put your hand in cold water, a “warm” opponent processes is being stimulated, but you feel that warmth only once you withdraw your hand from the water. And the pleasure of overindulging in sweet desserts is likely to be followed by an unpleasant reaction that arises some time after you stop eating.
- Avoid overexposure to pleasurable stimuli. This does not mean that you should minimize or avoid direct pleasure! Just be aware that too much of a good thing too often can backfire — and be aware WHY that is so. By remaining vigilant, you need only to moderate the intensity and frequency of pleasant stimuli to ensure that the opponent processes do not build up. For example, eating small portions of delicious foods, and spacing out meals — or even individual bites — will tend to reduce the level the opponent processes (cravings) that would otherwise reinforce appetite and cravings. When you go for that second cup of coffee, you may marginally increase your alertness in the short term, but realize that you are at the same time continuing to stimulate a reactive opponent process, counteracting the caffeine high, that may lead to increased tiredness later on. There is a biological argument for moderation!
- Use unpleasant and stressful stimuli to indirectly build pleasure. This is one of the most powerful insights of the opponent-process theory. By judiciously exposing ourselves to intermittent stresses, of sufficient intensity and frequency, we activate in our bodies and psyches some powerful opponent processes, which in turn result in heightened pleasure and satisfaction. Depending on the type of stimulus, these indirect pleasures can be short-lived or more sustained. Stressful or unpleasant stimuli can therefore be thought of as a form of “psychological hormesis”: The nervous systems is activating certain pleasurable inhibitory processes in order to defend against and build tolerance to stress. These pleasure-generating defense mechanisms are real, biological processes which operate in our nervous systems. One well known example is the production of endorphins, our natural opiates, which can be produced by engaging in strenuous exercise. Endorphins literally help us to endure the pain of exercise by providing a counteracting pleasure. So by increasing the intensity and frequency of stress exposures, we are not just building tolerance–we are actively building up a sustained background “tone” of pleasurable emotions. This is very much in line with what the Stoics called “tranquility”. As explained on the Stoicism page, Stoic tranquility is not apathy or a lack of feeling! On the contrary, it is a positive sense of equanimity, contentment, and happiness that endures and supports us. It is the opposite of depression; you might even call it “elevation”.
- Indirect pleasure is superior to direct pleasure. So we have learned that we can paradoxically use pain or discomfort to indirectly cause pleasure. But is there any reason to think that the pleasure resulting from running, hard work, cold showers, or skydiving is superior to the pleasure from sweet desserts or scratching an itch? Aren’t they equivalent? Doesn’t any pleasure, whether direct or indirect, nevertheless have the potential to lead to addiction? This is an interesting question, but I think the opponent-process theory makes the case that indirect pleasures — those that results as reactions to stress — are superior. There are two main reasons for this: First, according to Solomon, opponent-processes are “sluggish”; they take time to build, and decay more slowly. They continue even when the stimulus stops. And unlike direct pleasures, which may be more intense, there is no sudden withdrawal reaction when they stop, hence no “craving”. They tend to fade slowly. Second, the initial unpleasant stimulus — exercise, work, cold sensations — must be sufficiently unpleasant to be effective. This initial unpleasantness will always be a “barrier” that requires conscious effort to face and overcome. If it starts to become “addictive”, it is easier to let this unpleasant barrier stand in the way. It is easy to decide not to go running or take a cold shower if one becomes concerned it is becoming too habit-forming or detrimental to one’s health.
- Use unpleasant stimuli to counteract addictive pleasures. This is one of the most interesting, and I think unexplored, applications of the opponent-process theory. Addictions are characterized by increased cravings. These arise when opponent process build up in reaction to pleasurable primary stimuli that are too intense and frequent. The craving can become a sustained background “tone” that is always there when the pleasurable stimulus is absent. And the “savings” effect makes the opponent cravings come back more easily. But we can overpower these cravings by deliberately introducing unpleasant stimuli at the same time as the addictive cravings, in order to generate new pleasurable opponent processes. The key is to time the unpleasant stimuli to coincide with cravings or withdrawal, and make them sufficiently intense and frequent, that one builds up sufficient background pleasure tone to counteract the unpleasant anxiety that typically accompanies addictions. So fight cravings by adding a new stressful activity like high intensity exercise, cold showers, or intermittent fasting! It may also help explain why cue exposure therapy — exposing oneself to the forbidden fruit without partaking — can often be more effective in extinguishing addictions than merely abstaining or avoiding the addictive stimulus. It is possible that active cue exposure might generate a type of acute “stress” that “burns out “the original craving with an opposing pleasure. This is like fighting fire with fire!
- Don’t abuse pain and stress. Despite the potential benefits of controlled stress and unpleasant stimuli to indirectly induce sustained pleasure or “elevation”, this approach is easy to misinterpret or apply incorrectly. Some might take this to be a justification for masochism or self-harm, but it is not. The key here is to carefully think through the consequences of one’s actions. Does the application of the stress or unpleasantness result in an objective strengthening of your body and mind — or does it lead to physical or psychological harm? Depressed teens sometimes engage in a practice called “cutting” to relieve their depression and apathy, because it can actually reactivate pleasure or a rush that fills a gap and can become addictive. Most likely, this pleasure can be explained in terms of opponent processes that release some of the same endorphins or other neurotransmitters as exercise does. But one needs to distinguish between objectively harmful activities like cutting and beneficial habits like exercise or cold showers. Far from injuring oneself, these beneficial uses of stress and “pain” act to act to build strength, resilience, and long-term happiness.
- Optimize your stimulation schedule. Be aware of critical decay durations and savings effects of opponent processes, for both pleasant and unpleasant stimuli. Addictions and cravings can be minimized by reducing the frequency of exposure to pleasure-triggers to allow enough time for any cravings to decay. The next time you are mindlessly wolfing down bite after bite of an addictive snack like popcorn or candy, try spacing out bites to allow the craving sensations to die off between bites and see whether you end up satisfied with fewer bites. On the flip side, if you are finding it hard to get started on a healthy habit like strenuous exercise, cold showers, or fasting, it may be that you need to increase the frequency and intensity of the new habit until it takes. According to Solomon, it will become increasingly pleasant if you do this.
Since becoming aware of the opponent-process theory, I applied it to myself in two instances recently:
- On the pleasure side, I reduced my craving for alcohol by drinking less frequently, and limiting the amount that I drink. The pleasure remains, but the daily cravings have disappeared. I’ve documented this on the Discussion Forum of this blog.
- On the pain side, I have increased my enjoyment of cold showers by never missing a day, by lengthening the showers, and by making sure to expose my most sensitive body parts to the coldness. This has significantly increased the pleasure I feel, and it comes on more quickly while in the shower (within 10-15 seconds, versus previously more than a minute) and the warm, exhilarating post-shower feeling lasts all morning. I’m happy all the time, and I definitely feel less stress.
Think about how this might apply to your own situation. Are there pleasures in your life that tend to result in cravings when they are absent? Can you think of ways to introduce healthful but somewhat unpleasant stress into your life in a way that builds your resilience and at the same time a deeper level of satisfaction and sustained pleasure? Can you use this indirect pleasure to displace cravings or dissatisfaction? And in both cases, how aware are you of the relationship between the intensity and frequency of the stimuli, and the tendency to foster opposing processes that turn pleasures into pains, and pains into pleasures?
The potential applications are infinite!